1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
// Daniel Grzegorzewski
// while (clock()<=69*CLOCKS_PER_SEC)
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")

#define MP make_pair
#define PB push_back
#define ST first
#define ND second
#define int long long

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

//X.find_by_order(k); - zwraca iterator na k-ty element (numeracja od zerowego)
//X.order_of_key(k); - zwraca liczbę elementów ostro mniejszych niż k

typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef long long LL;

void init_ios() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
}

const uint64_t SEED = chrono::steady_clock::now().time_since_epoch().count();
mt19937_64 rng(SEED);

int n, m, q;
map<PII, int> ma;
VI d;

int solve(int n, int m) {
  if (n == 0 || m == 0)
    return 0;
  if (n < m)
    swap(n, m);
  auto it = ma.find({n, m});
  if (it != ma.end())
    return it->ND;
  int ind = upper_bound(d.begin(), d.end(), m) - d.begin();
  --ind;
  int cnt = (n/d[ind])*(m/d[ind]);
  int remA = n%d[ind];
  int remB = m%d[ind];
  return ma[{n, m}] = cnt+min(solve(n, remB)+solve(remA, m-remB), solve(remA, m)+solve(n-remA, remB));
}

signed main() {
  init_ios();
  cin >> n >> m >> q;
  while (q--) {
    int x;
    cin >> x;
    d.PB(x);
  }
  if (n%d[0] != 0 || m%d[0] != 0) {
    cout<<"-1\n";
    return 0;
  }
  cout<<solve(n, m)<<"\n";
}